image: panic: semaphore: bad release

I created a tool to synchronize the gcr.io image to the docker hub, but after running for a period of time, I get a panic: semaphore: bad release

INFO[2020-04-21 17:31:14] sync k8s.gcr.io/k8s-tpu-operator:0.1 => docker.io/gcrxio/k8s.gcr.io_k8s-tpu-operator:0.1
INFO[2020-04-21 17:31:14] sync k8s.gcr.io/k8s-tpu-operator:0585ea2d8131291cc041329e32bb7c81263cf7c5 => docker.io/gcrxio/k8s.gcr.io_k8s-tpu-operator:0585ea2d8131291cc041329e32bb7c81263cf7c5
INFO[2020-04-21 17:31:14] sync k8s.gcr.io/kube-addon-manager-ppc64le:v6.4-alpha.3 => docker.io/gcrxio/k8s.gcr.io_kube-addon-manager-ppc64le:v6.4-alpha.3
INFO[2020-04-21 17:31:14] sync k8s.gcr.io/k8s-jupyterhub:0.2 => docker.io/gcrxio/k8s.gcr.io_k8s-jupyterhub:0.2
INFO[2020-04-21 17:31:18] sync k8s.gcr.io/k8s-tpu-operator:1.0 => docker.io/gcrxio/k8s.gcr.io_k8s-tpu-operator:1.0
panic: semaphore: bad release

goroutine 81928 [running]:
golang.org/x/sync/semaphore.(*Weighted).Release(0xc007f61ae0, 0x1)
        /Users/natural/gopath/pkg/mod/golang.org/x/sync@v0.0.0-20190227155943-e225da77a7e6/semaphore/semaphore.go:98 +0x1f5
github.com/containers/image/copy.(*imageCopier).copyLayers.func1(0xb, 0xc00066b180, 0x47, 0x15d3896, 0x0, 0x0, 0x0, 0x0, 0xc00028b900, 0x31, ...)
        /Users/natural/gopath/pkg/mod/github.com/containers/image@v3.0.2+incompatible/copy/copy.go:489 +0x241
created by github.com/containers/image/copy.(*imageCopier).copyLayers.func2
        /Users/natural/gopath/pkg/mod/github.com/containers/image@v3.0.2+incompatible/copy/copy.go:497 +0x1f6

For speed, I am performing image synchronization in 20 concurrency, this is my code

type Image struct {
	Repo string
	User string
	Name string
	Tag  string
}

type SyncOption struct {
	Timeout    time.Duration
	Limit      int
	User       string
	Password   string
	NameSpace  string
	Proxy      string
	QueryLimit int
	Kubeadm    bool
}

func sync2DockerHub(image *Image, opt SyncOption) error {
	destImage := Image{
		Repo: DefaultDockerRepo,
		User: opt.User,
		Name: image.MergeName(),
		Tag:  image.Tag,
	}

	logrus.Infof("sync %s => %s", image, destImage.String())

	ctx, cancel := context.WithTimeout(context.Background(), opt.Timeout)
	defer cancel()

	policyContext, err := signature.NewPolicyContext(
		&signature.Policy{
			Default: []signature.PolicyRequirement{signature.NewPRInsecureAcceptAnything()},
		},
	)
	if err != nil {
		return err
	}
	defer func() { _ = policyContext.Destroy() }()

	srcRef, err := docker.Transport.ParseReference("//" + image.String())
	if err != nil {
		return err
	}
	destRef, err := docker.Transport.ParseReference("//" + destImage.String())
	if err != nil {
		return err
	}

	sourceCtx := &types.SystemContext{DockerAuthConfig: &types.DockerAuthConfig{}}
	destinationCtx := &types.SystemContext{DockerAuthConfig: &types.DockerAuthConfig{
		Username: opt.User,
		Password: opt.Password,
	}}

	m, err := copy.Image(ctx, policyContext, destRef, srcRef, &copy.Options{
		ReportWriter:          ioutil.Discard,
		SourceCtx:             sourceCtx,
		DestinationCtx:        destinationCtx,
		ProgressInterval:      1 * time.Second,
		ForceManifestMIMEType: manifest.DockerV2Schema2MediaType,
	})
	if err != nil {
		return err
	}

	storageDir := filepath.Join(ManifestDir, image.Repo, image.User, image.Name)
	// ignore other error
	if _, err := os.Stat(storageDir); err != nil {
		if err := os.MkdirAll(storageDir, 0755); err != nil {
			return err
		}
	}

	return ioutil.WriteFile(filepath.Join(storageDir, image.Tag+".json"), m, 0644)
}